Lucy had seven times as much money as Sarah. After Lucy spent $13 and Sarah spent $4, Lucy had $21 more than Sarah. How much did Lucy have in the end?
| |
Lucy |
Sarah |
| Before |
7 u |
1 u |
| Change |
- $13 |
- $4 |
| After |
7 u - $13 |
1 u - $4 |
Comparing Lucy
and Sarah
in the end |
$21 more |
|
If Sarah was given another $21, the amounts that Lucy and Sarah each had in the end would be the same.
7 u - 13 = 1 u - 4 + 21
7 u - 1 u = 13 + 17
6 u = 30
1 u = 30 ÷ 6 = 5
Amount that Lucy had in the end
= 7 u - 13
= 7 x 5 - 13
= 35 - 13
= $22
Answer(s): $22
